Fluid intake screen

ABSTRACT

A screen for intake of fluid. The screen includes parallel and spaced rods, filtration material, a fitting, and structural members. The rods may be distributed in a cylindrical configuration. The filtration material, which can be spirally wrapped wire, is disposed around the rods to define an interior volume. The fitting is disposed at an end of the rods and adjacent to the filtration material. Each structural member, which can be elongated bars, is interposed between adjacent rods. The structural members are welded to the adjacent rods, and the adjacent rods and the structural members are welded to the fitting to increase the effective weld area, the tensile strength of the connection, and potentially the overall strength of the screen. The screen may be used for a variety of fluids and installations, and is particularly suited to use in water wells.

CROSS-REFERENCE TO RELATED APPLICATION

This application is a continuation of application Ser. No. 14/331,915filed Jul. 15, 2014, which claims the benefit of U.S. ProvisionalApplication 61/846,399, filed Jul. 15, 2013, and titled “Fluid intakeScreen,” the contents of which are incorporated herein by reference inits entirety.

BACKGROUND

Screens are used in water wells to retain sand and gravel in the wellhole, and prevent debris from being pumped from the well. The screenaids in the proper development of the well structure. In some cases,these wells can be deep underground. When the screens are installed,there is often a great deal of weight hanging from the screen as it islowered into the well bore. This can cause the screen to fracture orseparate, releasing other screen or piping that is attached to thescreen into the well. When this problem occurs, the well must beredrilled or extreme measures taken to remove the fractured portion ofthe screen cylinder.

Screens with higher weight or geomechanical pressure have beentraditionally made from heavier construction. The screen may includewire spirally wrapped and welded to a set of longitudinal rods. Thetensile or weight bearing strength of the screen is then dependent atleast in part on the strength of the longitudinal rods. Larger rods maybe used to provide higher screen strength. While the rods themselves maybe able to resist the overall loading, the load capacity of the assemblyis also dependent on the bond between the screen rods and any fittingsthat are used to attach the screen to pipes or additional screens. Thesefittings are often threaded male or female ends welded to each end ofthe screen cylinder. With a conventional screen, the maximum weld areafor welding rods to the fitting at the end of the screen may beequivalent to the cross sectional area of the longitudinal rods.Considering that the type of welds normally used to attach the screen tothe fittings does not allow for full use of the available weld area, thestrength of the screen for structural resistance may be limited by thisjoint.

SUMMARY

Embodiments disclosed herein may include a supplemental structuralmember or bar running parallel to the screen rods and attaching to theend fitting. These supplemental bars are attached to the longitudinalscreen rods, and provide a greater attachment area resulting in a largerallowable weld area. Consequently the screen may accommodate a largerload and in some embodiments may be considered a heavy duty screen usinga deep well fitting attachment.

In accordance with one embodiment disclosed herein, a screen for intakeof fluid is provided. The screen includes a plurality of substantiallyparallel, spaced rods, filtration material, a fitting, and a pluralityof structural members. The plurality of rods is distributed about alongitudinal axis, has a length, and terminates at a first end and asecond end. The filtration material is disposed around a portion of thelength of the plurality of rods to define an interior volume, and isconfigured to allow fluid to pass there through while preventingpatticulate matter greater than a predetermined size from passingtherethrough. The fitting is disposed at the first end of the pluralityof rods and adjacent to the filtration material, and is configured to beproximate to an end of each of the rods. Each structural member isinterposed between adjacent rods and has a first end proximate to thefirst end of the plurality of rods and a second end spaced from thesecond end of the plurality of rods. The structural members are weldedto the adjacent rods, and the adjacent rods and the structural membersare welded to the fitting.

In some embodiments, the filtration material includes wire spirallywrapped around the plurality of rods to form slots for receiving fluidinto the interior volume. In some embodiments and in combination withany of the above embodiments, each end of the plurality of rods issubstantially in a plane perpendicular to the longitudinal axis. In someembodiments and in combination with any of the above embodiments, theplurality of rods is arranged in a cylindrical configuration. In somesuch embodiments, the fitting is a substantially cylindrical ring. Insome embodiments and in combination with any of the above embodiments,the welding of the structural member to the adjacent rods and thefitting effectively increases the weld area for the connection of therods to the fitting. In some such embodiments, the increased weld areaincreases the tensile strength of the connection of the rods to thefitting.

In some embodiments and in combination with any of the aboveembodiments, the structural members are elongated bars. In some suchembodiments, the elongated bars are substantially parallel to theadjacent rods. In some such embodiments, the adjacent rods define aspace therebetween, and every space receives a bar. In other suchembodiments, the adjacent rods define a space therebetween, andalternating spaces receive a bar. In some such embodiments, at least thefirst end of each bar is welded to the fitting. In some suchembodiments, the first end of each bar is substantially in the plane atthe first end of the rods.

In some embodiments and in combination with any of the aboveembodiments, each structural member comprises a plurality of pieces. Insome such embodiments, each piece is an elongated bar.

In accordance with another embodiment disclosed herein, another screenfor intake of fluid is provided. The screen includes a plurality ofsubstantially parallel, spaced rods, wire, a cylindrical end fitting,and a plurality of bars. The plurality of rods is distributed about alongitudinal axis in a cylindrical arrangement, has a length, andterminates at a first end and a second end substantially in a planeperpendicular to the longitudinal axis. The wire is spirally wrappedaround the plurality of rods to define an interior volume and to formslots for receiving fluid into the interior volume. The cylindrical endfitting has a central axis and is disposed at the first end of theplurality of rods and adjacent to the wire. The central axis is alignedwith the longitudinal axis of the plurality of rods. Each bar isinterposed between adjacent rods and has a first end proximate to thefirst end of the plurality of rods and a second end spaced from thesecond end of the plurality of rods. The bars are welded to the adjacentrods and the adjacent rods and the bars are welded to the end fitting.

In accordance with another embodiment disclosed herein, a method ofmaking a screen for intake of fluid is provided. A plurality of rods isdisposed in a substantially parallel, spaced, cylindrical arrangementabout a longitudinal axis, with the plurality of rods having a lengthand terminating at a first end and a second end substantially in a planeperpendicular to the longitudinal axis. Filtration material is disposedaround at least a portion of the length of the plurality of rods todefine an interior volume with the filtration material configured toallow fluid to pass through it white preventing particulate mattergreater than a predetermined size from passing through. A cylindricalend fitting is having a central axis is disposed at the first end of theplurality of rods and adjacent to the wire. The central axis iscoincident with the longitudinal axis of the plurality of rods. Aplurality of bars is provided, and each bar is disposed between selectedones of adjacent rods. Each bar has a first end proximate to the firstend of the plurality of rods and a second end spaced from the second endof the plurality of rods. The bars are welded to the adjacent rods, andthe adjacent rods and the bars are welded to the end fitting. In someembodiments, disposing filtration material around at least a portion oflength of the rods includes spirally wrapping wire around the pluralityof rods to define the interior volume and to form slots for receivingfluid into the interior volume.

BRIEF DESCRIPTION OF THE DRAWINGS

For a more complete understanding, reference should now be had to theembodiments shown in the accompanying drawings and described below. Inthe drawings:

FIG. 1 is a perspective view of one or more embodiments of screens in astacked position for storage.

FIG. 2 is a plan view of a screen according to one embodiment.

FIG. 3 is a cross-section view of a portion of the screen of FIG. 2taken along line 3-3 of FIG. 2.

FIG. 4 is a cross-section view of a portion of the screen of FIG. 2taken along line 4-4 of FIG. 2.

FIG. 5 is a detail perspective view of a portion of the end of thescreen of FIG. 2.

FIG. 6 is a plan view of a screen according to another embodiment.

FIG. 7 is a cross-section view of a portion of the screen of FIG. 6taken along line 7-7 of FIG. 6.

FIG. 8 is a detailed perspective view of a portion of the end of thescreen of FIG. 6.

FIG. 9 is a detailed perspective view of a portion of the ends thescreens of FIGS. 2 and 6.

DETAILED DESCRIPTION

The following detailed description of embodiments refers to theaccompanying drawings, which illustrate specific embodiments. Otherembodiments having different structures and operation do not depart fromthe scope of the present disclosure.

Certain terminology is used herein for convenience only and is not to betaken as a limitation on the embodiments described. For example, wordssuch as “top”, “bottom”, “upper,” “lower,” “left,” “right,”“horizontal,” “vertical,” “upward,” and “downward” merely describe theconfiguration shown in the figures. Indeed, the referenced componentsmay be oriented in any direction and the terminology, therefore, shouldbe understood as encompassing such variations unless specifiedotherwise. Throughout this disclosure, where a process or method isshown or described, the method may be performed in any order orsimultaneously, unless it is clear from the context that the methoddepends on certain actions being performed first.

Referring to the drawings, where like reference numerals refer to thesame or similar parts, FIG. 1 shows one or more embodiments of screens40 for a water well, stacked for storage, and FIG. 2 shows an embodimentof an individual screen 40. When installed, the screens 40 may beconnected end to end in vertical alignment. Although the outside surfaceof the screens 40 appears smooth, the screens 40 are formed withopenings and are shown with spirally wrapped wires 42 that form slots asserve as filtration material.

In one embodiment, the screens 40 may include as filtration material aplurality of spaced filter wires supported on support rods. In oneembodiment, the screens may include “Vee-Wire” type screens. In oneembodiment, the screens 40 may include as filtration material plates(not shown) having perforations, slots, or other filter-type openings.In one embodiment, the spacing and sizes of wires 42 vary along thelengths of the screens 40. In one embodiment, the screens 40 may includeas filtration material any combination of wires 40 and plates. Thescreens may be fabricated based on the same principle as the embodimentsdisclosed in U.S. Pat. No. 6,663,774, filed on Oct. 16, 2001 andspecifically with respect to the filter wires 28 and the support rods 20described therein, and embodiments like those disclosed in U.S. Pat. No.7,425,264, filed on Jul. 18, 2005 and specifically with respect to thewires 16 and the support rods 17 described therein, the contents of bothof which patents are herein incorporated by reference in their entirety.

In the “Vee-Wire” type of screen, a filtering surface is formed by wires42 with a V-shaped cross-section, meaning that they each have agenerally triangular-shaped cross-section and which are parallel atconstant intervals, the space between wires framing the slots of thescreen. As shown in FIG. 3, these wires 42 are welded to support rods 44oriented essentially perpendicularly with respect to the wires 42, andmay be relatively thin in order to maximize the effective opening of theslots. Such a screen 40 may have the advantage of being very strong andbeing resistant to clogging. The screen 40 allows a liquid, for examplewater, to pass through it, while preventing particulate matter greaterthan a certain size from entering the interior of the screen 40. Eachwire 42 includes a face surface and two side surfaces which converge toa point. The wires 42 are aligned, side-by-side, with their facesurfaces lying in a plane, which, as will be further discussed below,creates the outer surface of the screen 40 and defines an interiorvolume 43.

In one method of manufacture, the screen 40 may be constructed byinserting a number of support rods 44 into a series of notches equallyspaced around the circumference of a specially designed wheel (notshown). In the case of square, rectangular, or V-shaped profile rods,the notches in the wheel may be generally triangular in shape. In thisway, the support rods 44 are secured around the wheel and extendsubstantially perpendicularly to the wheel to create a cylinder ofsupport rods 44. The wheel, and thus the cylinder of rods 44, is thenrotated and a wire 42 is continuously and spirally wrapped around therotating cylinder of rods 44. At each point where the wire 42 intersectsa rod 44, an electrical charge is conducted through the intersection andthe wheel, thereby welding the wire 42 to the rod 44. The result is ascreen cylinder formed with a plurality of longitudinally extending rods44 spirally-wrapped in a wire 42. The rods 44 may be substantiallyparallel, spaced from each other, and distributed about a longitudinalaxis, with the plurality of rods 44 having a length and terminating at afirst end and a second end. Each end of the plurality of rods 44 mayterminate substantially in a plane perpendicular to the longitudinalaxis. The rods 44 may be arranged in, for example, a cylindricalconfiguration.

When using wires of V-shaped cross-section, a channel is created betweenopposing side surfaces of consecutive wires. Because of the triangularshaped cross-section of the wires in one embodiment, the channelsbetween consecutive wires open away from the plane defined by the facesurfaces of the filter wires. Put another way, the filter channels donot have parallel walls, but instead flare from the face surfaces to thepoints of the wires.

FIG. 2 shows an embodiment of a screen 40 with end fittings that areweld rings 50, 52 at each end. Rods 44 are not shown in FIG. 2 forclarity, but are shown in FIGS. 3-5. In FIG. 3 the configuration of rods44 and wires 42 may be seen. The rods 44 in this embodiment are angledsuch that a corner of each rod 44 contacts the wire 42, and the wire 42is welded to each rod 44 at that point. The rods 44 maybe at a center tocenter distance of A, and have a spacing of B. The rings 50, 52 (notshown in FIG. 2) may have inside diameter (I.D.) 54, the saddle (alsonot shown), which supplies the rods 44, may have a diameter 56 (which isalso the screen barrel inside diameter), the wire 42 may have an insidediameter (I.D.) 58, and the screen may have an outside diameter (O.D.)60. The gap between the wire 42 and the weld rings 50, 52 preferablydoes not exceed the dimension of the slot between the wires 42. The wire42, i.e., filtration material, may be disposed around at least a portionof the length of the plurality of rods 44 to define the interior volume43, with the wire 42 configured to allow fluid to pass through the slotswhile preventing particulate matter greater than a predetermined sizefrom passing through.

As shown in FIGS. 4 and 5 in one embodiment of a screen 40, in betweenthe rods 44 at the ends of the screen 40 are supplemental bars 70, whichmay also be referred to as structural members, tabs, or spacers. Thebars 70 may be elongated and substantially span the distance betweenpairs of adjacent rods 44 and be substantially parallel to the rods 44.In the embodiment shown the bars 70 are located between every other pairof rods 44. Alternatively, the bars 70 could be in the spaces betweenall adjacent rods 44, or could be at less frequent intervals with thenecessary spacing dependent on the application. The number of rods 44and their spacing may also be varied.

In this embodiment the bars 70 are rectangular and are welded to therods 44, but other shapes are feasible and may be desirable depending onthe application. The bars 70 are preferably flush with the ends of therods 44, and may be relatively short, not as long as the rods 44 and notextending the entire length of the screen 40. In the embodiments shownherein, the bars 70 are very short relative to the rods 44. The bars 70may each have a first end proximate to the first end of the plurality ofrods and a second end spaced from the second end of the plurality ofrods. The rods 44 and the bars 70 are welded to each other and to theweld rings 50, 52, which in some embodiments are end fittings, orfittings. The weld rings 50, 52 may be configured to be proximate to anend of each of the rods 44. The weld rings 50, 52 may each be, forexample, a substantially cylindrical ring to match the configuration ofthe plurality of rods 44 and having a central axis that is aligned withthe longitudinal axis of the plurality of rods 44. In this manner thearea of the weld is increased by the increased area provided by the endof the bar 70, which increases the strength of the weld and the loadthat the screen 40 can bear. With the bars 70 the tensile strength ofthe connection of the rods 44 to each weld ring 50, 52, and of thescreen 40 overall, may increase, especially if the weakest part of thescreen was previously the connection of the rods 44 and the endfittings, in this case the weld rings 50, 52.

In one embodiment, the screen is 24 inch O.D. There may be 70 rods 44spaced evenly around the cylinder that extend the full length betweenthe weld rings 50, 52, and the rods 44 could be, for example, ⅜ inchessquare in cross-section. The rods 44 could have a 1.042 inches center tocenter distance A, and have a spacing B of 0.519 inches. The weld rings50, 52 could be 6 inches long with a 24 inch O.D. and, for example, 0.5inches thick for a 23 inch J.D 54. The screen O.D. 60 could be 24inches, and the saddle diameter 56 (or screen barrel I.D.) could be22.189 inches. The wire I.D. 58 could be 23.024 inches. The overalllength of the screen 40 could be 240 inches, with the 6 inch long weldrings 50, 52 at each end for a 228 inch long wire portion of the screen40. The bars 70 in this embodiment are rectangular and may be, forexample, ⅜ inch by ½ inch by 2 inches long.

Weld symbols are shown in the figures to disclose the embodiment of ascreen 40 shown in FIGS. 2-6. However, it should be understood thatdifferent welds could be used as determined by one of ordinary skill inthe art. As shown in FIG. 2, the weld rings 50, 52 may be welded to therods 44 and bars 70 with a fillet weld 62 on the surface of the weldring 50, 52 that is on the interior of the screen 40. Such a fillet weld62 is called for in the embodiment shown at each end of the screen 40for all rods 44 and all bars 70. The fillet weld 62, which may be, forexample, ⅜ inch. As shown in FIG. 4, the rods 44 and the bars 70 may bewelded to each other with a bevel weld 64 on each side of each bar 70.In one embodiment, at least one end of each bar 70 is welded to the weldring 50, 52.

In addition, it may be considered that the bars 70 disclosed herein, asstructural members, may be provided in more than one piece. For example,each structural member may be provided as two or more elongated bars,and as such, more than one bar may be inserted between adjacent rods 44to make up a structural member.

FIG. 6 shows another embodiment of a screen 40 that is made up of twoshorter screens 80, 82. The first shorter screen 80 has a fitting at oneend that is a collar 84 attached to a weld ring 50 and a fitting at theother end that is a weld ting 86. The second shorter screen 82 has afitting at one end that is a weld ring 88 and a fitting at the other endthat is a longer weld ring 52. The central weld rings 86, 88 are weldedto each other to form the full length screen 40. The collar 84 may bewelded, for example, to a weld ring on an adjacent screen or pipe, or inanother embodiment could be female threaded to receive a male threadedfitting. The weld ring 52 may be welded, for example, to a weld ring onanother adjacent screen. Rods 44 are not shown in FIG. 6 for clarity,but are shown in FIGS. 7 and 8. The configuration of rods 44, wires 42,and weld rings 50, 52, 86, 88 are the same as that shown in FIG. 3.

As shown in FIGS. 7 and 8, similarly to FIGS. 4 and 5, in between rods44 at the ends of the screens 80, 82 are supplemental bars 70. The bars70 may substantially span the distance between pairs of adjacent rods44, and in the embodiment shown are again located between every otherrod 44. As previously discussed, the bars 70 could be between every rod44, or could be at less frequent intervals with the necessary spacingdependent on the application. In this embodiment, the bars 70 are squareand are welded to the rods 44, but other shapes are feasible and may bedesirable depending on the application; for example, the rectangular andsquare bars 70 shown herein may also be considered to represent round,elliptical, triangular, or asymmetrical cross-sectional shapes. Inaddition, the rotational orientation of the bars 70 may differ from thatshown. Once again, in this embodiment the bars 70 are preferably flushwith the ends of the rods 44, and may be relatively short, not as longas the rods 44 and not extending the entire length of the screen 40. Therods 44 and the bars 70 are welded to the weld rings 50, 52, 86, 88. Inthis manner the area of the weld is increased by the increased areaprovided by the end of the bar 70, which increases the strength of theweld and the load that the screen 40 can bear.

In the embodiment of the screen 40 of FIGS. 6-8, the dimensions may bethe same as in the embodiment of FIGS. 2-5, with the followingadditions. The weld rings 50, 52 at the ends of the screen 40 could be 6inches long with a 24 inch O.D. and, for example, 0.5 inches thick for a23 inch I.D 54. The central weld rings 86, 88 could be similar but each2 inches long. The wired portion of the screens 80, 82 could each be 232inches, with the overall length of the screen 40 being 483 inches. Thebars 70 in this embodiment are square and may be, for example, ⅜ inch by⅜ inch by 2 inches long.

Additional welds that may be applicable to the embodiment of a screen 40shown in FIGS. 6-8 include a V weld 94 all around where the central weldrings 86, 88 are joined, which may be finished to a smooth convexcontour by grinding. The weld dimension in one embodiment may be 0.19inches. Again, it should be understood that different welds could beused as determined by one of ordinary skill in the art. The weld rings50, 52, 86, 88 may be welded to the rods 44 and bars 70 with a filletweld 62, on the surface of the weld ring 50, 52, 86, 88 that is on theinterior of the screen 40. Accordingly, such a fillet weld 62 is calledfor in the embodiment shown at one end of each of the shorter screens80, 82 for all rods 44 and all bars 70. The fillet weld 62 may be, forexample, ⅜ inch. The rods 44 and the bars 70 may be welded to each otherwith a bevel weld 64 on each side of each bar 70.

FIG. 9 shows the interior of an embodiment of a screen 40 at one end.Rods 44 extend to the weld ring 52 where there is a weld 62 to connectthe rods to the weld ring. The weld 62 also connects the bar 70 to theweld ring 52, and a weld 64 connects the bar 70 and the rods 44together.

Materials for the screens may be selected by one of ordinary skill inthe art as appropriate for the particular application, but one materialthat may be used is AISI 316 stainless steel. For 316 Stainless Steel,design features, characteristics, and strengths in one embodiment ofscreens in accordance with the previously described embodiments for awell are as follows:

Feature English Units Metric Units Nominal Size 24 in 610 mm EstimatedTotal Well 1,500 ft 457 meters Depth Estimated Feet of 850 ft 259 metersScreen Design Slot Size 0.070 in 1.8 mm Approx. O.D. 23.94 in 608 mmScreen Barrel I.D. 22.19 in 564 mm Approx. Clear I.D. at 21.69 in 551 mmFittings Approx. Weight Per 100 lbs 46 kg Foot Wire Width 0.248 in 6.3mm Wire Height 0.488 in 12.4 mm Calculated Collapse 2323 PSI 16 kg/sq.cm Strength Open Area 22.0% 22.0% Intake Area 199 sq. inch. 4,206 sq.cm/meter Transmitting Capacity- 62 gpm/ft 13.5 ips/meter at 0.1feet/second Support Rod Diameter 0.530 in 13.5 mm (circle through allcorners of rod) Number of Rods 70 70 Cross-Sectional Rod 9.84 in 63.51sq. cm Area (total) Design Yield Strength 30,000 PSI 2,109 kg/sq. cmCalculated Tensile 206,700 lbs 93,800 kg Strength Maximum 103,400 lbs46,900 kg Recommended Hang Column Load 265,000 lbs 120,500 kg

Embodiments disclosed herein may provide relatively more open area forintake of fluid than conventional screens, with added overall strengthfor applications in dewatering and water supply, and may be ofparticular benefit for water wells in the mining industry.

Although specific embodiments have been illustrated and describedherein, those of ordinary skill in the art appreciate that anyarrangement which is calculated to achieve the same purpose may besubstituted for the specific embodiments shown and that the embodimentsherein have other applications in other environments. This applicationis intended to cover any adaptations or variations of the presentdisclosure. The following claims are in no way intended to limit thescope of the disclosure to the specific embodiments described herein.While the foregoing is directed to embodiments of a screen andcomponents used in water wells, other and further embodiments may bedevised without departing from the basic scope thereof, and the scopethereof is determined by the claims that follow.

What is claimed is:
 1. A screen for intake of fluid, comprising: aplurality of substantially parallel, spaced rods distributed about alongitudinal axis, the plurality of rods having a length and terminatingat a first end and a second end; filtration material disposed around aportion of the length of the plurality of rods to define an interiorvolume, the filtration material configured to allow fluid to passtherethrough while preventing particulate matter greater than apredetermined size from passing therethrough; a first fitting at thefirst end of the plurality of rods and adjacent to the filtrationmaterial; a second fitting at the second end of the plurality of rodsand adjacent to the filtration material; a plurality of first structuralmembers located proximate the first fitting, each first structuralmember interposed and welded between adjacent rods at the first ends,and the adjacent rods and the first structural members are welded to thefirst fitting; and a plurality of second structural members locatedproximate the second fitting, each second structural member interposedand welded between adjacent rods at the second ends, and the adjacentrods and the second structural members are welded to the second fitting.2. The screen of claim 1, wherein the filtration material comprises wirespirally wrapped around the plurality of rods to form slots forreceiving fluid into the interior volume.
 3. The screen of claim 1,wherein each first end of the plurality of rods is substantially in afirst plane perpendicular to the longitudinal axis and each second endof the plurality of rods is substantially in a second planeperpendicular to the longitudinal axis.
 4. The screen of claim 3,wherein the plurality of rods is arranged in a cylindricalconfiguration.
 5. The screen of claim 4, wherein at least one of thefirst fitting and the second fitting is a substantially cylindricalring.
 6. The screen of claim 1, wherein the welding of the firststructural member to the first end of the adjacent rods and the firstfitting effectively increases the weld area for the connection of therods to the first fitting.
 7. The screen of claim 6, wherein theincreased weld area increases the tensile strength of the connection ofthe rods to the fitting.
 8. The screen of claim 1, wherein the first andsecond structural members are elongated bars.
 9. The screen of claim 8,wherein the elongated bars are substantially parallel to the adjacentrods.
 10. The screen of claim 8, wherein the adjacent rods define aspace therebetween, and every space receives a bar.
 11. The screen ofclaim 8, wherein the adjacent rods define a space therebetween, andalternating spaces receive a bar.
 12. The screen of claim 8, wherein atleast the first end of each bar is welded to the fitting.
 13. The screenof claim 12, wherein the first end of each bar is substantially in theplane at the first end of the rods.
 14. The screen of claim 1, whereineach structural member comprises a plurality of pieces.
 15. The screenof claim 14, wherein each piece is an elongated bar.
 16. The screen ofclaim 1, wherein at least one of the first and second fittings comprisesa collar.
 17. A screen assembly, comprising: a pair of the screens ofclaim 1, wherein the first and second fittings of each screen areconfigured to operably join the pair of screen about the longitudinalaxis.
 18. The screen assembly of claim 17, wherein at least one of thefirst and second fittings of each screen comprises a central weld ringand wherein the central weld rings of each screen are operably, weldedtogether.
 19. The screen assembly of claim 17, wherein at least one ofthe first and second fittings of each screen comprises a collar.